Introduction: Cardiovascular disease (CVD) is the leading cause of mortality in low-income countries (LICs). Neighborhood social vulnerability has been associated with increased CVD risk in high-income countries, but the relationship is unknown in LICs. Our objective was to determine the association between neighborhood social vulnerability and prevalent CVD in urban Haiti. Hypothesis: We hypothesize that adults living in neighborhoods with increased social vulnerability will have a greater prevalence of hypertension (HTN) and CVD. Methods: We used cross-sectional enrollment data from the Haiti CVD Cohort study, a population-based cohort of adults ≥18 years living in Port-au-Prince distributed across 97 census blocks. To quantify vulnerability, we created a Haiti-specific Neighborhood Social Vulnerability Index (NSVI) based on the US CDC Social Vulnerability Index. The NSVI included three socioeconomic variables (income, sex, education), two household variables (single parent household, household with child <18 years), and six neighborhood stress and well-being variables (neighborhood cohesion, neighborhood violence, perceived stress, food insecurity, depression, social support). Each variable was determined using validated questionnaires. NSVI was calculated for each census block, which were stratified into quartiles. HTN was defined as SBP ≥140 mmHg, DBP ≥90, or on antihypertensive medications; CVD included heart failure, stroke, myocardial infarction, and angina, defined using adjudicated criteria. HTN and CVD prevalence were calculated for each NSVI quartile. Associations between NSVI quartile and HTN or CVD were quantified using individual-level multivariate logistic regression to adjust for confounders. Results: Among 2932 participants, median age was 40 years (IQR 28-55) and 58% were female. Age-standardized prevalence of HTN and CVD was 32.3% and 13.8%, respectively. The age-standardized prevalence of HTN and CVD was 35.7% and 17.3% across 4 th NSVI quartile blocks, compared to 29.1% and 14.1% across 1 st quartile NSVI blocks (p < 0.001). After adjusting for age, BMI, smoking, and alcohol use, participants living in 4 th NSVI quartile blocks had a greater risk of HTN (Adjusted Odds Ratio (aOR) 1.42; 95% CI 1.07-1.88; p-value 0.01) and CVD (aOR 1.36; CI: 0.99-1.88; p-value 0.06) compared to participants in the 1 st NSVI quartile blocks. NSVI was significantly associated with HTN in males but not females; conversely, NSVI was significantly associated with CVD in females and not males. Conclusions: Individuals living in neighborhoods with the greatest social vulnerability had a higher prevalence of HTN and CVD. Even in a setting of severe poverty such as urban Haiti, gradients in social vulnerabilities are associated with CVD disparities. Screening for social vulnerabilities should be incorporated into CVD prevention and treatment interventions in LICs.